Rotaviruses have been shown to be the single most important cause of infantile gastroenteritis (Holmes, I. H., Rotaviruses, in The Reoviridae Ed. W. K. Joklik, Plenum: 395-399) and are also important pathogens in many animal species, particularly calves and piglets. In many third world countries rotavirus infection causes significant infant mortality. The World Health Organization has recommended that a vaccine against human rotavirus be developed as soon as possible (Bull. W. H. O. 1983, 61: 251-254).
At present, five serotypes of human rotavirus are known (Hoshino, et al. 1984, J. Infect. Dis. 149: 694-702 and Albert et al., Arch. Virol. 93: 123-130) and it has previously been shown that the virus serotype is determined by the major outer capsid glycoprotein VP7 (also called gp34) (Kalica et al. 1981, Virology 112: 385-390; Dyall-Smith et al. 1983a, J. Virol. 46: 317-320; Kantharidis, et al. 1983, J. Virol. 48: 330-334; Sonza et al., 1983, J. Virol. 45: 1143-1146; Dyall-Smith, et al. 1984, Nucleic Acids Res. 12: 3973-3982). A vaccine effective against rotaviral infection may require representative viruses or VP7 protein antigens of all known serotypes in order to elicit protective immunity against all human serotypes (Gaul, et al. 1982, J. Clin. Micro. 16: 495-503) due to the poor cross reactivity of VP7 protein antigens.